This invention concerns a stable hematology reference control reagent suitable for use in common medical diagnostic procedures to analyze and test a patient's blood sample for making classic determinations with respect to the blood sample and more particularly, provides a novel diagnostic test control reagent which includes ingredients providing the control reagent with the capability of monitoring the desired platelet parameters of the patient's blood sample as well as the seven classic determinations or parameters with respect to the blood sample. In other words, the invention provides a single hematology reference control reagent which can be used for monitoring the precision and accuracy of the classic hematology measurements or determinations, i.e., red blood cell count (RBC), white blood cell count (WBC), hematocrit (HCT), the hemoglobin (HGB), the mean corpuscular hemoglobin (MCH), the mean corpuscular volume (MCV) and the mean corpuscular hemoglobin concentration (MHC) and as a control also for monitoring the accuracy and precision of the measurement and determination of platelet parameters such as platelet count, mean platelet volume, platelet volume fraction (thrombocytocrit) and platelet distribution width using the same whole blood product that is conventionally used for the control for the previously mentioned classical hematology parameters.
It is a common medical diagnostic procedure to analyze and test a blood sample of a patient in order to make certain classic determinations with respect to the blood sample. This procedure is an important diagnostic tool for the physician. As a result of modern technological advances, there have been automated instruments developed which will accept a patient's blood sample and process the sample automatically and continuously to provide the parameters or determinations described above as the seven classic parameters of a blood sample. An instrument which will accept a patient's blood sample and process same automaticlly and continuously to provide these seven classic parameters or determinations enumerated is described and claimed in U.S. Pat. No. 3,549,994. Said U.S. Pat. No. 3,549,994 provides acceptable definitions of such parameters and illuminates the problems to be solved in handling of the blood sample as it is drawn through the fluid system of said patented apparatus.
Coulter Electronics, Inc. of Hialeah, Fla., the assignee of this patent application, also manufactures and sells other blood cell counting and analyzing instruments which are less sophisticated than the apparatus of said U.S. Pat. No. 3,549,994 but which are operated to determine red blood cell and white blood cell counts, hemoglobin concentration and their collected indices such as HCT, MCV, MCH and MCHC.
In the use of such an instrument which may be referred to herein, at times, by the registered trademark "COULTER COUNTER" owned by Coulter Electronics, Inc., there is required to be employed a multi-purpose diluent comprising an electrolyte which enables electronic measurements to be made by the COULTER COUNTER.RTM. instrument. A suitable multi-purpose diluent for use in blood analysis by an electronic instrument such as the COULTER COUNTER.RTM. is described and claimed in U.S. Pat. No. 3,962,125.
A suitable reagent for determining leukocytes and hemoglobin in the blood sample by means of a high speed automated hematology instrument such as the COULTER COUNTER.RTM.is described in U.S. Pat. No. 3,874,852 issued Apr. 1, 1975. The reagent described and claimed in said patent is a lysing reagent for converting hemoglobin to a chromogen for making the desired determinations.
Coulter Electronics, Inc. has heretofore provided a hematology reference control for accuracy in electronic estimation of blood cell values capable of functioning with the diluent and lysing reagents discussed above. One such reference control has been sold by Coulter Electronics under its registered Trademark 4C which comprises a modified whole blood hematology reference control prepared from fresh human blood. Fixed erythrocytes were added to simulate leukocytes. This reference control had seven known blood values which were stable for a desired period of time. The reference control was prepared for use with the COULTER COUNTER.RTM. and accessory mean corpuscular volume hematacrit computers and hemoglobinominators. When used with the blood diluent identified above, it served as a check on accuracy of dilution, red blood cell counts, and MCV-Hematocrit computer calibration. After addition of a lysing reagent, the reference control served as a check on white blood cell counts. Thus, the so-called 4C.RTM. hematology reference control was utilized in the COULTER COUNTER.RTM. for electronic estimation of red and white blood cells, hematocrit, mean corpuscular volume, hemoglobin, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. Other hematology reference controls also were available for use with the COULTER COUNTER.RTM. which comprise stabilized human red blood cell suspensions such as the product known as Baker Haem-C.RTM. of J. P. Baker Chemical Corporation or the product known as CH-60.RTM. of the Dade Reagent Company of Hialeah, Fla. However, none of these mentioned hematology control reagents were capable of being used for testing accuracy of measurements of platelet parameters. Consequently, for making such determinations, a separate control had to be employed for monitoring the platelet parameters. In other words, a separate control had to be employed for making the platelet determinations and the hematology control reagents for making the seven classical measurements or parameter determinations could not be employed for platelet control functions.
Further, prior art platelet counting has been inadequate because of the lack of stable platelet controls containing other blood components, namely, red blood cells. Thus, the increasing availability of instrumentation for distinguishing platelets from red blood cells and automatically performing platelet counts has created a great need for stable control products which contain both platelets and red blood cells.
The single hematology control of this invention includes the capability of monitoring platelet parameters as well as the seven classic parameters of hematology measurements. This hematology control has the advantage in that it eliminates the need for a separate control material for monitoring platelet parameters and provides a more meaningful determination of platelet parameters in that the potential interfering red blood cells, red blood cell metabolites, etc., normally observed in patient blood specimens are present in the control material of the invention. This is especially important for platelet counts performed with manual methodologies using light microscopy or phase microscopy, where great skills on the part of laboratory technologists is required to adequately differentiate blood platelets from red blood cells and other cellular materials. The subject invention also provides a means for monitoring these measurements using manual methodology or automated or semi-automated hematology instruments for hematology measurements along with a means for testing accuracy of platelet count, mean platelet volume, platelet volume fraction (thrombocytocrit) and platelet distribution based on the use in the reference control of the present invention of the same whole blood product which is conventionally used for control of the classic seven hematology parameters.